Handling Errors - Best Practices

Easiest non-cluttering ways to handle errors

## TLDR;

function goLike<F extends  (...args: any) => any, E = unknown>(func: F, ctx: unknown = undefined) {
    return (...args: Parameters<F>): [ReturnType<F> | null, E | null] => {
        try {
            const res = func.apply(ctx, args)
            return [res, null]
        } catch (e) {
            return [null, e as E]
        }
    }
}

Identifying the Problems

Callbacks

Everyone is aware of the popular "callback hells", but we mostly see those with respect to success responses, what if you need to handle the errors as well.

type cb<T = unknown> = (v: T) => void
type someFun<A = unknown, S = unknown, E = unknown> = (args: A, successCb: cb<S>, errorCb: cb<E>) => void

declare const fun1: someFun
declare const fun2: someFun
declare const fun3: someFun

function fun4(opt: unknown, successCb: cb, errorCb: cb) {
    fun1(opt,
        result1 => {
            fun2(result1, 
                result2 => {
                    fun3(result2, 
                            result3 => {
                                successCb(result3)
                            },
                            error3 => {
                                errorCb(error3)
                            }
                        )
                },
                error2 => {
                    errorCb(error2)
                }
                )
        },
        error1 => {
            errorCb(error1)
        }
        )
}

Promises

Async Await